Effects of zinc application on the growth and photosynthetic characteristics of pecan at the seedling stage

Pecan (Carya illinoinensis) is sensitive to Zn, which is involved in basic physiological and biochemical processes. To explore the growth and physiology of pecan in response to Zn application, we used 1-year-old annual grafted seedlings (Pawnee) and applied four concentrations of Zn fertilizer (0.05, 0.10, 0.20 and 0.40 g center dot plant(-1)); a control (CK; no Zn fertilization) was also included. The growth characteristics, anatomical structure of the leaves and photosynthesis were assessed. Compared with the CK, photosynthesis and chlorophyll (Chl) fluorescence parameters, leaf area and leaf structure significantly increased at Zn concentrations of 0.05 and 0.10 g center dot plant(-1). In addition, growth of pecan at the seedling stage increased in response to moderate Zn application. In contrast, treatment with 0.20 and 0.40 g center dot Zn center dot plant(-1) dramatically decreased these physiological indices and inhibited pecan growth. The results show that moderate soil Zn application promotes pecan growth and development by increasing photosynthesis. However excess Zn concentrations were not conducive to seedling growth. The concentration of 0.1 g center dot Zn center dot plant(-1) was best when considering long-term soil Zn applications, providing a theoretical foundation for microelement management of pecan.

Automated summary

The study found that moderate soil Zn application can promote the growth and development of pecan by increasing photosynthesis; however, excess Zn concentrations can inhibit pecan growth. The concentration of 0.1 g center dot Zn center dot plant(-1) was found to be the most effective for long-term soil Zn applications, providing a theoretical foundation for microelement management of pecan.